Chapter 6

WATER RESOURCES

FACTS THAT MATTER

•Approx. 71% of the earth surface is covered with water but fresh water constitute only about 3% of the total water. Fresh water availability varies over space & time.


Water Resources of India

•India accounts for about 2.45% of world's surface area, 4% of world water resources & about 16% of world population. A very small proportion is of human use.

•Total water available from precipitation is about 4,000 cubic km. Surface water & groundwater is about 1869 cubic km. of this only 60% can be put to use.


Surface Water Resources

•Four major sources of surface Water -Rivers, Lakes, Ponds and tanks.

•Estimated mean annual flow is 1869 cubic km. Of this, due to topographical & other constraints only 690 cubic km. of the surface water can be used. Although Ganga. Brahmaputra and the Indus rivers account for 1/3rd of the total area of the country.

They have 60% of surface water resources. Most of the southern rivers have been harnessed though it is yet to be done for Ganga & Brahmaputra basins.


Groundwater Resources

•Water which percolates down and flow as subsurface water is groundwater (underground water). Total replenishable groundwater resources is about 4332 cubic km. Ganga & Brahmaputra basins have about 46% of the total replenishable groundwater resources. Ground water utilisation is high in the river basins lying in north-western region and parts of south India and in the states of Punjab, Haryana, Rajasthan & Tamil Nadu. States of Chhattisgarh, Odisha, Kerala utilise less of it. Moderate use is in Gujarat, Uttar Pradesh, Bihar, Tripura, Maharashtra, etc.


Lagoons and Backwaters

•A number of lagoons & lakes have formed along the indented coastline of India.

•Kerala, Odisha & West Bengal have vast surface water resources in these water bodies and is used for fishing, irrigation etc.


Water Demand & Utilisation

•To few this growing population in our agrarian economy, many development o irrigation & multipurpose projects have been taken up-like Bhakra-Nangal, Sara Sarovar, Chambal valley, Damodar Valley etc. India's water demand is dominated Dy irrigational needs.

•Agriculture accounts for 89% of surface water and 92% of ground water utilisation While for Industrial sector it is 2% and 85% respectively. Domestic sector uu more of surface water (9%) than underground water (3%).


Demand of Water for Irrigation

Irrigation is needed because of

(a) Spatio-temporal variability in rainfall in India

(b) Large areas are dry-have deficient rainfall and drought prone.

(c) Winter & Summer season are mostly dry in most parts. So irrigation is essential for farming.

(d) Erratic/break in monsoon requires irrigation in the rainier parts as well.

(e) Water intensive crops require more water.

(f) Irrigation makes multiple cropping possible

(g) Irrigated areas have higher productivity.

(h) HYV seeds require assured water supply for optimum production.

(I)To increase production of crops to feed the growing population, irrigation necessary to grow crops throughout the year, even in dry season.


Punjab, Haryana & Western Uttar Pradesh have > 85% of net sown area under irrigation. In Punjab (76%) & Haryana (51%) is irrigated though wells & tube wells. Ultimately leading to groundwater depletion in these states. Over withdrawal in states of Rajasthan & Maharashtra has increased fluoride concentration in groundwater (increase arsenic concentration in West Bengal).


Emerging Water Problems

•With increase in population both demand & per capital availability are getting affected. Demand in increasing while availability is decreasing. Increasing pollution of groundwater through industrial effluents, agricultural pesticides, domestic sewage also limiting the availability of usable water resources.


Deterioration of Water Quality

•Water quality refers to purity of water without unwanted foreign, substances. It gets polluted by foreign (toxic substances) matters-which make it unfit for human use as well as adversely affect the aquatic systems and sometimes deep down & affect groundwater.


Water conservation & Management

•It is imperative to efficiently conserve and manage the increasing demand for fresh water & its declining availability.

•Besides developing various water saving technologies and methods, efforts should be made to prevent pollution. Watershed development, rainwater harvesting, water recycling, reuse & other methods should be adopted for supply in the long run.


Prevention of Water Pollution

•Available water resources and degrading rapidly.

•Pure water quality is retained in less populated ares. In plains it is used intensively for domestic, agricultural, Industrial purposes which ultimately creates different pollutants.

•The Central Pollution Control Board in collaboration with State Pollution Control Board, monitors water quality of national aquatic resources at 507 stations. Their data reveal:

  • Major Pollutants are organic and bacterial contamination, toxic metals, fluoride & nitrates along with agricultural, domestic & other industrial effluents.

  • Polluted rives-Yamuna, Sabarmati, Gomti, Vaigai, Musi, Ganga.

  • Measures: Legislative Provision is water (Prevention & Control of Pollution) Act 1974 and Environment Protection Act 1986 were enforced-Though not implemented effectively

•Water Cess Act, 1977, meant to reduce pollution also was ineffective

•Need to generate public awareness about importance of water & impacts of water polution. Only Public participation can help reduce pollution.


Recyle and Reuse of Water:

•To improve fresh water availability it is imperative to promote recycle & reuse of water.

•Use of lesser quality water e.g., reclaimed waste-water should be an attractive option for industrial cooling purpose, fire fighting, etc.

•in urban areas used domestic water can be use for gardening.

•This will ensure better quality water for drinking & cooking.

There is enormous scope for replenishing water through recycling.


Watershed Management

•It is efficient management and conservation of surface and groundwater resources by preventing run off and storing and recharging groundwater.


Objective

•Conservation, Regeneration, Judicious use of all resources (land, water, plants & animals) & as well as humans in a watershed.

•Maintaining balance between natural resources & Society

•Community participation in the Projects.

Central & State Govt. Programmes:

•Haryali sponsored by Central government which aims at enabling the rural population to conserve water for various purposes (drinking, irrigation, fisheries & afforestation)- under the Gram Panchayats with people participation.

•Neeru-Meeru-(Water & You) in Andhra Pradesh

•Arvary Pani Sansad-in Alwar, Rajastharn.

•Tamil Nadu has made water harvesting structure compulsory.

•There is need to generate awareness regarding the benefits of watershed management that this system is the key to ensure water availability on a sustainable basis.


Rainwater Harvesting (RWH)

•It is a method to capture & store rainwater for various purposes.

•used to recharge groundwater aquifers.

•A low cost eco-friendly technique for preserving every drop of water by guiding rain water to bore wells, pits and wells.

•It increases water availability.

•Checks declining groundwater table

•Improves quality of groundwater through dilution of contaminants.

•Prevents soil erosion & flooding

•Arrests salt water intrusion

It is an old technique to preserve rainwater through surface storage like lakes, ponds, tanks, etc. In Rajasthan they are called kund or Tanka.


Advantage of RWH:

•Conserve precious water resource on rooftops & open spaces.

•Decreases the community dependence on groundwater for domestic use.

•Helps in bridging the gap between demand & supply

•Saves energy to pump groundwater as recharge leads to rise in groundwater table.

•The urban areas as well as the rural parts can benefit from RWH as growing water demand has outstripped the supply

Some solutions for water problems:

•Desalinisation of water in coastal areas & brackish water in arid areas.

• transfer of water from water surplus to deficit areas

•Inter linking of rivers.

•Pricing of water to prevent household wastage.



We hope CBSE/MP Board Class 12th "Geography Part B " Chapter 6 "Water Resources" will help you.

Written By - HIMANSHU SHARMA